This invention relates to warning devices for the hearing impaired or for those working in an environment where warning sounds are hidden by ambient noise and that provide non-auditory type signals to the users.
Presently there are available warning devices that respond to a warning sound such as the buzzing of a smoke detector, the ringing of a telephone, the honking of a car horn and the like by providing a noticeable signal such as visible light or a vibration to a wearer of the device. Such devices are particularly useful for the hearing impaired. U.S. Pat. No. 3,786,628 to Fossard et al issued Jan. 22, 1974 describes such a device that, for example, may be connected to an alarm clock, placed under a pillow, and provides a vibration to the user when the alarm of the clock is activated. Still another U.S. Pat. No. 4,297,677 issued Oct. 27, 1981 to Lewis et al pertains to a portable device that can detect changes in the ambient sound level produced for example, by a warning sound superimposed on the ambient sound level and produces a visible light or some tactile sensation to alert the wearer of the device that the change in the sound level has occurred. Other prior art devices such as that described in U.S. Pat. No. 4,731,603 comprise a transmitter unit that responds to a warning signal and transmits a communication signal in the form of infrared light or a high frequency sound to a receiver worn by a user. The transmitter then in turn alerts the wearer through vibration. In U.S. Pat. No. 4,853,674, a system having a plurality of transmitter modules each associated with and monitoring the output of some signalling device can be used to alert the user that one of the monitored events has occurred.
The frequencies of telephone rings, alarms, and smoke detectors may vary considerably from one location to another often have different frequencies. None of the prior art devices, however, has the capability of being adapted to be used with a variety of different type of warning sounds that might be expected at such various locations. Thus, it would be highly advantageous to have a portable device that could effectively memorize a particular warning sound and then alert the user that the memorized warning sound has occurred. Such a device would have great application for people who travel, for example, and wish to be alerted that the phone in a hotel room is ringing or the smoke alarm is sounding. It would be further advantageous to have a portable device that could memorize and distinguish between a plurality of warning sounds and alert the user which sound is occurring. Finally, it would be still more advantageous to have a portable sound detecting device that could memorize a warning sound and distinguish that sound from ambient sound levels and alert the user of the occurrence of the sound.